Wet blasting machine



NOV- 20, 1951 w. l. GLADFELTER ETAL 2,576,008

WET BLASTING MACHINE ATTORNEYS N0 20, 1951 w. l. GLADFELTER ETAL 2,576,008

o WET BLASTING MACHINE Filed Sept. 9, 1949 2 SHEETS-SHEET- 2 l. IGI/7' WIA/00 W WM5 V VE H H VAS/0N WIA/DOW 5m l VMYW Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE WET BLASTING MACHINE Wiltie I. Gladfelter and Ralph Garver, Hagerstown, Md., assignors to Pangborn Corporation, Hagerstown, Md., a corporation of Maryland Application September 9, 1949, Serial No. 114,844

15 Claims.

This invention relates to blasting machines and aims to provide a wet blasting machine of high efficiency and simple and compact construction.

Among the objects of the invention, severally and interdependently, are the following: To provide in such a machine nov'el means for maintaining in agitated condition the liquid suspension or slurry of abrasive material. To provide therein novel means for Ventilating the cabinet. To provide therein simple .and effective means for clearing the slurry from the slurry pump and blast gun. To provide therein a novel and easily cleaned means for intercepting dust laden droplets drawn 01T in the Ventilating of the blast chamber. To provide in such a machine an improved air admission arrangement. To provide improved combinations, sub-combinations and elements contributing to the aforesaid objects.

Further objects and advantages of the invention will be apparent from the following description of an exemplary embodiment thereof.

The invention comprises the novel features and combinations hereinafter disclosed and claimed.

VIn the accompanying drawings forming a part of the specification:

Fig. 1 is a more or less diagrammatic side elevation partly in section of an exemplary embodiment'of the invention.

Fig. 2is a front elevation thereof.

, As shown in Figs. 1 and 2, a machine of the class described comprises .a cabinet or housing I enclosing a blasting chamber 2 and a slurry hopper 3. The housing I in the form shown is provided in oneof its walls with a vision window 4 and armhcles 5 with which are associated flexible sleeves 6 terminating in gloves 1, so that .the operator may hold and manipulate the worlnor the'blast gun, or both, within the machine.'

The blast gun in the form shown comprises a gun body I0 of any conventional or other form, having an inlet II for compressed air or other propelling Huid, supplied through a exiblehose I2, and an inlet I3 for the abrasive slurry supplied through the flexible line IA. The hoses I3 and I4 pass through the top or roof of the blasting` plenishing the same.

As is best shown in Fig. 1, the slurry pump I1 draws slurry from a suction pipe 22 having its inlet 23 not at the bottom of slurry storage body in hopper 3, but at an elevated position therein, proximate to and preferably above the dividing line 24 between the sediment and the supernatant liquid when the slurry is allowed to.

settle. The suction line 22 is provided as shown, with a stop valve 25. y

The discharge line I from the pump I1 is further provided with a return' line 26 which discharges upwardly into the bottom of the hopper 3 through the valve 21. The return or branch line 2t in the form shown is provided below the valve 2 with a fitting 28,Which` also has connected thereto a drain cock 29.

The pump I 1, when of the centrifugal impeller type shown, is driven in any suitable manner, eX- emplied by electric motor 30 and belt drive 3l.

As is further shown in Fig. 1, the installed machine is also provided with water piping comprising a water supply connection 32 from which extend branch lines 33, 34 and 35, provided respectively with stop valves 36, 31 and 38. The branch lines 33 and 34 connect, respectively, with the filter-wash and window-wash lines, hereinafter described. The branch line 35 connects in the form shown to the suction side of pump l1.

With the slurry circuit, above described, the machine being charged with slurry, and valves 25 and 21 being open, operation of the pump I1 effects a continuous circulation of slurry in the slurry circuit 23, 25, 22, I6, 26, 28, 21 and upwardly through the slurry body in hopper 3, thus thoroughly agitating the slurry body in the hopper and maintaining adequate uniformity of suspension of the slurry at all times. With valves I8, 25 and 21 closed and with valve 38 and drain cock 29 (Fig. 2) open, clear water may be passed through the pump and out the drain cock to iiush the pump clear of abrasive, with the pump operating, or not operating, as desired. By closing drain cock 29 and opening valve 21, clear water may be passed throughthe pump i1 and into the bottom of the hopper 3 for filling or re' With valves 25, 21 and 29 closed, and valves 38 and I8 open, clear water may be admitted to the pump inlet and may be supplied therefrom through line I5 to clear abrasive from this line and from the gun I0, when desired.

` With valves 21 and 29 open the contents of the emplied herein by the provision of refuse cans 40 and 4|.

In the illustrative embodiment shown in the drawings, the cabinet is provided with a suitable Work supporting means, shown as a work platform comprising a perforated plate 45 carried on supporting rods 46, and with side doors J operableA to place Work in or remove it from the machine. These doors may be of any desired form, and for compactness may comprise vertically slidable door panels carried in suitable guideways (not shown) In large machines these doors may be counterbalanced as by cable supported weights running in weight-guide tubes 5I as indicated by broken lines in Fig. 2.

Below the work platform 45, the slurry hopper 3 is preferably provided with a removable screen.

element 52, for straining the slurry returning to the hopper from the blasting chamber.

.The valved water line 34, previously mentioned, inthe form shown leads through a knee-controlled valve 55 and thence through conduit 56 to a Window wash spray pipe 51, placed close to and above the inner side of vision window 4. A branch line 58 with control valve 59 connects to a similar spray pipe 60 similarly related to the glass illuminating panel 8| which is interposed between the lighting fixtures 62 (shown as of the fluorescent tube type) and the blasting chamber 2. Suitable drip troughs 63 and 64 are provided to receive the used wash water, and in the form shown are piped to deliver it to a suitable disposal point as one of the refuse cans 48 or 4l.

The light compartment 65 in the form shown, is closed by a front access door 68, and is provided with air inlet means, shown as a grilled opening 61 in the top of the chamber 65. In the illustrated embodiment the light chamber 65 is also provided with an air discharge duct 68 (Fig. l) which extends slotwise above the Vision window 4, and the Ventilating air is drawn into the blasting chamber 2 through the light compartment and through this duct. With this arrangement the air entering through duct E8 is directed sheet- Wise across the vision window 4. Deposit of slurry splatter on the window 4 is thus retarded.

The fog of slurry droplets produced in the chamber 2 by the blasting operation Vis drawn away from the vision Window in the 'form of device shown in the drawings, and into a Ventilating outlet 1! near the lower rear of the chamber 2. The .Ventilating air and fog are drawn thence through a duct 1| and under a wash water deflectingl baffle 12 to the inner side of a cylindrical filter screen 13, arranged with its axis vertical in the form shown. The filter screen 13 preferably consists of a generally cylindrical selfsupporting screen member 14- of wire mesh or the like, and a cloth sleeve 15 within said screen and secured to its ends. In the' form shown the sleeve 15 is somewhat longer than the screen 14 and has its ends turned back over the ends of the screen 14 and suitably clamped thereto. Such clamping may be Veffected by retaining rings slipped over the ends of the asenibly at 16, or by abutment with the housing shoulders as shown. There is thus provided a reinforced filter cloth body capable of allowing the air to pass therethrough While retaining the dust laden fog on its inner surface. The screen 13 is received on a flange or shoulder 11 in the inlet duct, and held in place in the exhaust housing 18 by a removable cover 19. A spray head 88 is arranged axially at one end of the screen for spraying wash water on its inner surface to wash down the accumulated material from time to time (the exhauster hereinafter described being stopped as a general rule during this wash down operation). The wash water bafle 12 deflects the washings lfrom the Ventilating duct 1l into a channel 8l provided with a. drain pipe 82, thereby avoiding dilution of the slurry. A duct 83 connects the exhaust housing 18 to a suitable exhauster, shown as a motor driven fan 84, which draws the Ventilating air through the Ventilating circuit and discharges it from the machine.

From the foregoing description it will be apparent that the present invention provides an improved machine of the type employing an abrasive suspended in a liquid which is delivered to the blasting nozzle by means of a pump, and in which velocity is imparted to the suspension as it flows through the blast projector or nozzle I0, as by the injection of compressed air or the like. For normal nozzle work an air pressure of about pounds per square inch is satisfactory.

In use of the machine, any suitable circulatory medium may be employed, for example, a medium comprising 300 mesh silica mixed into aV Vthin watery mud or slurry in a water carrier, with .or without added anti-caking ingredients well known to the art, such as calcium hydroxide for example, which may be employed for reducing the pump may almost immediately develop fullv discharge pressure. The discharged liquid is thus positively forced through the centerV of the settled abrasive mass and quickly opens a passage for the commencement of ythe resuspending agitation. The employmentv of the non-compressible liquid slurry as the .agitating medium,

and its introduction at the bottom of the hopper,l

also affords a highly economical, as well as a very positive and complete agitation, continuously during the operation of the machine. The arrangement of parts is simple and compact, and ai single spray head is able to effect washing of the entire surface of screen 13 due to its vertical cylindrical arrangement. The `admission of the Ventilating air through the lighting chamber and across the inner surface of the vision window increases the economy ofthe machine, especially since it enables operation for a greater time without stopping to clean the window, and also affords an improved View of the work.`

The organization described is thus particularly effective in minimizing the proportion of an operators time required to be spent in non-production operations. For thereasons above noted in detail,` a very short period of preliminary cir culation provides an adequately stirred-up liquidy mud or slurry, and the continued-upwardagitation of the sump contents automatically main. `tains the slurry in working condition.

During the operationofl the gun, the ventilating arrangements tend to draw the fog produced by blasting out of the operators line of sight and the illuminating, window cleaning, and filterwashingarrangements cooperate to minimize the amount of ,time required for these operations to thus increase the proportion of time applicable to productive Work. Similarly, the improved arrangements for flushing, draining, and washingout of the various slurry-containing portions of the machine, all aid in reducing the amount of time required for these purposes and thus in maintaining the machine in Work-producing condition for las large a proportion of the Workers time as possible.

We claim:

l.. In 'a wet blasting machine, and in combination, a circuit including a slurry storage body for a slurry of abrasive particles, pump mechanism having an outlet and an inlet, said outlet being connected to the bottom of the storage body` and the said inlet being connected to a slurry-receiving intake located in the storage body above the outlet a distance suflicient to receive a working amount of abrasive particles, for circulating slurry through said circuit and upwardly through said body for maintaining uniformity of suspension therein, a vblast projector, and means for delivering slurry from the discharge side of said pump circuit to said projector.

2. In a wet blasting machine, and'in combination, a circuit including a slurry storage body for a slurry of. abrasive particles, pump mechanism having an outlet and an inlet, said outlet being connected to the bottom of the storage body and the said inlet being connected to a slurry-receiving intakelocated in the storage body above the outlet a distance sufficient to receive a Working amount of abrasive particles, for circulating slurry through said circuit and upwardly through said body for maintaining uniformity of suspension therein, a blast gun, means for delivering slurry from the discharge side of said pump circuit to said blast gun, and means for delivering compressed air to said gun for projecting the slurry therefrom at blasting velocity.

3. In a wet blasting machine, and in combination, a slurry circuit including a slurry storage body. said slurry circuit including circulating pump mechanism having an inlet connected to draw slurry from the upper portion of said body, an outlet connected to discharge slurry into the lower portion of said body to prevent settling of the suspended particles in said body, a blast projector,A a conduit connected to supply slurry from said body to said blast projector, and a valve structure for isolating said slurry body from the pump outlet.

4. In a Wet blasting machine, and in combination, a slurry circuit including a slurry storage body, pumping means therein for circulating slurry through said circuit and body for maintaining uniformity of suspension therein, a blast projector, a connection from the discharge side of said pumping circuit to said projector, valve means for isolating said slurry body from said circuit. and means for admitting clear water to the circuit in advance of said pumping means to pass therethrough.

5. In a wet blasting machine, and in combination. a blasting chamber, a slurry hopper below said blasting chamber, a valved bottom connection to said hopper and a valved suction connection communicating with the upper portion of said hopper, a pump having its suction side connected to said suction connection and its delivering side connected to said bottom connection, a discharge valve connected to said bottom connection, a blast gun in said blasting chamber,

and a valved connection from the delivery side of said pump to said blast gun.

6. In a wet blasting machine, and in combination, a blasting chamber, means for projecting a slurry blast therein, a vision window in. a wall of said blasting chamber, means for applying wash water to the inner side of said Window, a lighting compartment adjacent said vision window for illuminating said chamber, a Ventilating suction duct leading from said chamber and means for,

admitting Ventilating airto said chamber through said lighting compartment, said air admitting means directing the admitted air across said vision window. I y

'7. In a blasting machine, and in combination, a blasting chamber, a vision window in awall'of said blasting chamber, means for applying wash water to the inner side of said window to clean thev same, a Ventilating suction duct leading from said chamber, and means for admitting ventilating air to said chamber, said last named means formed to direct the admitted air across said vision window.

8. In a wet blasting machine, and in combination, a blasting chamber, means for projecting a slurry blast therein, a ventilation outlet near the4 lower part of said chamber, a Ventilating duct leading therefrom to an exhauster, a vertical cylindrical cloth screen lter interposed in said duct, a spray head for discharging Wash water against at least the upper portions of the inlet surface of said lter, and means for deecting the wash water from said Ventilating duct.`

9. In a wet blasting machine, and in combination, a slurry blasting chamber, a Ventilating duct leading therefrom and having a rising portion, a vertical generally cylindrical cloth screen filter forming an upper portion of said duct, a removable cap closing the end of said duct therebeyond, an exhaust box surrounding said lter, means for connecting said exhaust box to an exhauster, a sprayer arranged axially of said lter for discharging wash water thereagainst, and a deector arranged above said rising portion for defiecting the wash water therefrom.

10. In a wet blasting machine, a Ventilating duct, a vertical generally cylindrical cloth screen iilter forming an upper portion of said duct, said lter comprising a generally cylindrical screen and a cloth sleeve within said screen and secured to the ends of said screen, a suction box about said cloth screen iilter, and a spray head :for delivering wash water against the inside of said cloth sleeve.

1l. As a sub-combination in a slurry blasting machine or the like, a cloth screen filter comprising a cylindrical self-supporting screen, a cloth sleeve within said screen and secured to the ends of said screen, an inlet duct having a shoulder for supporting one end of said screen, a cap for supporting and closing the outer end of the screen, an exhaust housing about the screen, means for spraying wash liquid on the inner surfaces of said sleeve, and means for diverting the wash water from said inlet duct.

12. In a wet blasting machine, and in combination, a slurry circuit including a slurry storage body, said slurry circuit including circulating pump mechanism having an inlet and outlet, said inlet being connected to draw slurry from the upper portion of the said body, and said outlet be1ng`conn'ected for discharging slurry into the lower 'portion of said body to prevent settling of` from the storage body to said blast projector, a

valve structure connected for isolating said slurry body from said pump outlet, and a drain'cock connected to said outlet.

13. In a slurry blasting machine, an air circulation system for withdrawing air laden with blasting dust from the machine, an air lter having a cloth lter element positioned insaid systemysaid element having a porous surface Vexposed to the circulating air for stopping particles carried along by the air and passing the air without the trapped particles, a spray mechanism connected for spraying wash liquid over said surface to periodically wash off the trapped particles and rejuvenate the lter element.

. 14:.l In a ,compact slurry blasting machine a blasting chamber, a slurry holder below said blasting chamber, an air circulation system for removal of dust laden air from said blasting chamber, said system including an air lter having a cloth lter element positioned above the blasting chamber, and vertically extending air ducts' connecting the lter with the blasting chamber, said lter element having a porous surface exposed to the air entering from the blasting chamber, for trapping and retaining particles carried along bythe air, and passing the air substantially free of said particles, a spray mechanism connected to periodically wash off the trapped particles and rejuvenate the filter element,1and diverting structure cooperating with the ducts to'keep the washings from running down into and diluting the slurry.

8, 15. In a slurry blasting machine: walls dening a blasting chamber; a slurry-storage body; a

blast projector, said blast projector being'located within the blasting chamber; a slurry conduit connected between the blast projector and saidk slurry storage body; a vision window in av Wall tion around said opening, a exible glove sealed to the other end of the sleeve to provide for the insertion and manipulation of an operators hand within the blasting chamber without the escapeV of slurry and dust from the machine.

WILTIE I. GLADFELTER. RALPH R. GARVER.

REFERENCES CITED The following references are of record inthe le of this patent:

UNITED STATES PATENTS Number Name Date p 1,511,025 Y Christoph Oct. 7, 1924 2,462,480 Eppler Feb. 22, 1949 2,493,215 Barnes Jan. 3, 1950A FOREIGN VPATENTS A Number Country Date 119,012 Australia Oct. 12, 1944 339,932 Great Britain Oct. 19, 1933 612,200 Great Britain Nov. 9, 1948, 649,263 Germany c Aug. 19, 1937 France Apr. 8, 1930 

